AoE x-Chapters, High-Speed op-amps section, DRAFT

[Joerg]

On 2019-07-16 06:56, John Larkin wrote:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.

And each would probably cost $2M+ on the market, leaky plumbing or not.
No 10 horses would drag me to live in S.F.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-07-15 16:31, Phil Hobbs wrote:

On 7/15/19 11:03 AM, Joerg wrote:
On 2019-07-15 07:10, John Larkin wrote:
On Mon, 15 Jul 2019 06:58:58 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-14 10:32, Phil Hobbs wrote:
On 7/14/19 9:59 AM, Joerg wrote:
On 2019-07-13 14:02, Winfield Hill wrote:
Phil Hobbs wrote...

On 7/13/19 4:26 PM, Joerg wrote:
On 2019-07-13 13:10, Phil Hobbs wrote:

So colour me stupid. What's so different about offsets
due to rectification vs. intrinsic imbalances, such that
they get multiplied by A_VOL and not A_VCL like all the
others?

Imbalances are static, they do not show up as spectrally
significant noise. Rectified RF is not constant and that's
the problem. GSM phones ...

Understood. But unless I misunderstand, you're claiming
that an op amp with A_VCL = 20 dB (say) multiplies the
rectified RF by A_VOL (100 dB) instead. That's what I'm
wondering about.


That's exactly how it is. The noise attacks inside the chip at the
first BJT pair so the closed loop gain no longer applies, it's at
full
open loop gain.

So feedback magically doesn't apply? How exactly does that work? It
works on every other source of offsets.


The RF is added after the feedback divider.

So is DC offset.


Yes, but it does not pulsate. The transitions are the problem. If it
were a constant RF carrier there would be not a problem other than
maybe an elevated noise level.



RF either comes in directly
through a plastic enclosure or via power cables and the like and then
re-radiated inside the box. The traces to IN+ and IN- form an unwanted
dipole antenna, the RF couples onto those and then affects both BJTs in
the first pair. It's like a comparator, the feedback loop is nearly
powerless. While it does regulate out slower effects it cannot handle
the sharp onset and drop-off of, for example, a GSM phone that seeks to
establish communication with a cell tower. The pulses is what gets
through and annoys, not DC.


If the forward gain of the opamp is slow, it's slow for both the
RF-induced offset and for the feedback.

We could Spice that, but we'd have to decide where inside the loop to
inject the RF offset.


Immediately at (inside) the BE junctions of the first pair. It's hard
to do because RF also attacks other BE junctions in there.

The problem is that such signals develop inside the opamp and the
feedback loop only notices it after the fact. "Oh s..t! Where did that
come from? Let's fight it!".

Okay, so you're talking about rectified components near or beyond the
loop bandwidth. I agree with that--there's not so much difference
between A_VOL and A_VCL up there. But that's because A_VOL isn't 100 dB
up there either.

Down at the 220 Hz GSM data rate, your average op amp has plenty of
speed to respond to rectified RF in the approved closed-loop manner.

Theoretically yes but it cannot handle the transients at the onset. When
that stuff is on a die it can take uncontrolled paths, and from what I
experienced seems to do so. Large output amplitudes.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jan Panteltje]

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?
What frequency is that?


>I bet they could have wireless LED night lights.

Long ago I lived not so far away from a TV tower:
https://en.wikipedia.org/wiki/Gerbrandy_Tower
about 100kW, I read they had at one point 400 kW running,
there are some FM radio antennas on it too.
I could get the video with a crystal detector on Ch 4 (about 65 MHz).
Designed and build my own transistor TV in school days.
Now it is all lower power digital terrestrial.

Tested my ham transmitter with a neon bulb in the garden

I would not want to live right next to such a tower,
all your electronic experiments will be affected by it.

 

[John Larkin]

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.

Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Joerg]

On 2019-07-15 20:06, Clifford Heath wrote:

On 16/7/19 12:21 pm, John Larkin wrote:
My experience with opamps rectifying RF on PC boards is that there are
usually several narrow resonances where it's very sensitive, in the
low 100s of MHz.

One of my (ex) competitors NMR temperature controllers, with a
thermocouple sensor, could be hard shut down with a GR signal
generator, from clear across the room.

An RF design friend of mine has had issues with parallel capacitors
(like 0.1uF/100pF) adjacent on a supply line. He's had quite high-Q
resonance between the 100pF and the parasitic inductance at between 400
and 900MHz. Traps, and he's not a "young player".

IME such small bypass cap values make no sense at all. Definitely not in
the days of MLCC. 0.01uF to 0.1uf in 0603 is fine. It's the layout that
counts, plus the proper use of large planes as "free" bypass capacitors.
This is part of my daily bread, helping engineers route and place vias
properly. "But that's less than 1/10th of an inch!" ... "Yes, but it
does matter here".

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-04-27 07:15, Tom Del Rosso wrote:

Joerg wrote:

1. EMI behavior of opamps. This is generally not understood at all by
engineers and (still!) not taught at universities from what young EEs
told me. A bipolar input stage will rectify RF at the first BE
junction, even stuff at cell phone frequencies. This rectification or
demodulation is very inefficient but since that is inside the loop
any resultying baseband AM will hit at full tilt because it happens
at "open loop".

Why only with opamps? Do you also get that effect in some transistor
amps?

Yes. 70's era stereo amps are a classic example.

As for example circuits that is a good idea but the only entities who'd
have a business case to build some are EMC consultancies and labs that
teach classes. Small market

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Tue, 16 Jul 2019 07:29:59 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-07-15 20:06, Clifford Heath wrote:
On 16/7/19 12:21 pm, John Larkin wrote:
My experience with opamps rectifying RF on PC boards is that there are
usually several narrow resonances where it's very sensitive, in the
low 100s of MHz.

One of my (ex) competitors NMR temperature controllers, with a
thermocouple sensor, could be hard shut down with a GR signal
generator, from clear across the room.

An RF design friend of mine has had issues with parallel capacitors
(like 0.1uF/100pF) adjacent on a supply line. He's had quite high-Q
resonance between the 100pF and the parasitic inductance at between 400
and 900MHz. Traps, and he's not a "young player".


IME such small bypass cap values make no sense at all. Definitely not in
the days of MLCC. 0.01uF to 0.1uf in 0603 is fine. It's the layout that
counts, plus the proper use of large planes as "free" bypass capacitors.
This is part of my daily bread, helping engineers route and place vias
properly. "But that's less than 1/10th of an inch!" ... "Yes, but it
does matter here".

I use 1 uF 0805 caps by default. Scattered around a power plane, close
to a ground plane, they work fine.

The oft-repeated "analysis" of paralleled, stepped-value bypass caps,
is nonsense. Lots of signal-integrity lore is nonsense.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 16 Jul 2019 14:18:41 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?

Megawatts.

>What frequency is that?

Everything. On a spactrum analyzer, the AM, FM, and TV bands are about
full. And the tower is used for police and fire comms too. It
overlooks the entire city, and then some.

I bet they could have wireless LED night lights.

Long ago I lived not so far away from a TV tower:
https://en.wikipedia.org/wiki/Gerbrandy_Tower
about 100kW, I read they had at one point 400 kW running,
there are some FM radio antennas on it too.
I could get the video with a crystal detector on Ch 4 (about 65 MHz).
Designed and build my own transistor TV in school days.
Now it is all lower power digital terrestrial.

Tested my ham transmitter with a neon bulb in the garden

Here's my Pockels Cell driver:

https://www.dropbox.com/s/mt2ym6ukuizoy9q/Neon_4.jpg?raw=1

I would not want to live right next to such a tower,
all your electronic experiments will be affected by it.

My company is about 2 miles away, in a wooden building in plain sight
of the tower, and we get a lot of RFI effects.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 16 Jul 2019 07:25:23 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-07-16 06:56, John Larkin wrote:
On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.


And each would probably cost $2M+ on the market, leaky plumbing or not.
No 10 horses would drag me to live in S.F.

I love this place. Most visitors see the parts of the city that we
never go to.

I have a mostly inaccessable/hidden loft outside of my office. I bet I
could put up a big, 100 sq feet at least, resonated loop antenna and
get enough RF to light up an LED. Some LEDs are visible in room light
at 1 uA, and in the dark at a few nA.

Can a loop antenna be multiple wavelengths long and do any good? The
"resonance" would actually be multiple cycles of transmission line
delay. That should work. What polarization to AM/FM/TV transmitters
use? Antennas are complicated.









--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Joerg]

On 2019-07-16 08:12, John Larkin wrote:

On Tue, 16 Jul 2019 07:29:59 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-15 20:06, Clifford Heath wrote:
On 16/7/19 12:21 pm, John Larkin wrote:
My experience with opamps rectifying RF on PC boards is that there are
usually several narrow resonances where it's very sensitive, in the
low 100s of MHz.

One of my (ex) competitors NMR temperature controllers, with a
thermocouple sensor, could be hard shut down with a GR signal
generator, from clear across the room.

An RF design friend of mine has had issues with parallel capacitors
(like 0.1uF/100pF) adjacent on a supply line. He's had quite high-Q
resonance between the 100pF and the parasitic inductance at between 400
and 900MHz. Traps, and he's not a "young player".


IME such small bypass cap values make no sense at all. Definitely not in
the days of MLCC. 0.01uF to 0.1uf in 0603 is fine. It's the layout that
counts, plus the proper use of large planes as "free" bypass capacitors.
This is part of my daily bread, helping engineers route and place vias
properly. "But that's less than 1/10th of an inch!" ... "Yes, but it
does matter here".

I use 1 uF 0805 caps by default. Scattered around a power plane, close
to a ground plane, they work fine.

The oft-repeated "analysis" of paralleled, stepped-value bypass caps,
is nonsense. Lots of signal-integrity lore is nonsense.

But it always makes for a good scare story, just like a lot of the
theories about global w... ...... bit my tongue here

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Tue, 16 Jul 2019 10:08:25 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-07-16 08:12, John Larkin wrote:
On Tue, 16 Jul 2019 07:29:59 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-15 20:06, Clifford Heath wrote:
On 16/7/19 12:21 pm, John Larkin wrote:
My experience with opamps rectifying RF on PC boards is that there are
usually several narrow resonances where it's very sensitive, in the
low 100s of MHz.

One of my (ex) competitors NMR temperature controllers, with a
thermocouple sensor, could be hard shut down with a GR signal
generator, from clear across the room.

An RF design friend of mine has had issues with parallel capacitors
(like 0.1uF/100pF) adjacent on a supply line. He's had quite high-Q
resonance between the 100pF and the parasitic inductance at between 400
and 900MHz. Traps, and he's not a "young player".


IME such small bypass cap values make no sense at all. Definitely not in
the days of MLCC. 0.01uF to 0.1uf in 0603 is fine. It's the layout that
counts, plus the proper use of large planes as "free" bypass capacitors.
This is part of my daily bread, helping engineers route and place vias
properly. "But that's less than 1/10th of an inch!" ... "Yes, but it
does matter here".

I use 1 uF 0805 caps by default. Scattered around a power plane, close
to a ground plane, they work fine.

The oft-repeated "analysis" of paralleled, stepped-value bypass caps,
is nonsense. Lots of signal-integrity lore is nonsense.


But it always makes for a good scare story, just like a lot of the
theories about global w... ...... bit my tongue here

I've seen absurd papers about bypassing... authored by capacitor
makers. There is one so co-authored paper, with someone from Xilinx,
that recommends three caps for *each* power ball on an FPGA. Hundreds
of caps per chip.

Modern FPGAs and CPUs have on-chip capacitance for the fast stuff.
They don't need heroic bypassing.

I saw one board being assembled in Japan, in an open-air
pick-and-place shop, that was putting 3000 bypass caps on each board.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Jan Panteltje]

On a sunny day (Tue, 16 Jul 2019 08:26:17 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<deqried1d0ifvnvldqr8arkkialcv1iakd@4ax.com>:

On Tue, 16 Jul 2019 14:18:41 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?

Megawatts.

That scares me.

What frequency is that?

Everything. On a spactrum analyzer, the AM, FM, and TV bands are about
full. And the tower is used for police and fire comms too. It
overlooks the entire city, and then some.




I bet they could have wireless LED night lights.

Long ago I lived not so far away from a TV tower:
https://en.wikipedia.org/wiki/Gerbrandy_Tower
about 100kW, I read they had at one point 400 kW running,
there are some FM radio antennas on it too.
I could get the video with a crystal detector on Ch 4 (about 65 MHz).
Designed and build my own transistor TV in school days.
Now it is all lower power digital terrestrial.

Tested my ham transmitter with a neon bulb in the garden

Here's my Pockels Cell driver:

https://www.dropbox.com/s/mt2ym6ukuizoy9q/Neon_4.jpg?raw=1

Yes, we discussed that before, just do not put the neon _in_ the coil,
it may scatter pieces of glass, I killed one that way, was lucky,
was a dual envelope neon tuning indicator... Maybe from some radar..

I would not want to live right next to such a tower,
all your electronic experiments will be affected by it.

My company is about 2 miles away, in a wooden building in plain sight
of the tower, and we get a lot of RFI effects.

In the TV studio building the roofs were metal to keep RFI out.
Then at some point we got interference from the electric trains,
there is a train station next to those studios.
Ground loops, miles and miles of coax, 6 TV studios in one big building.
Probably more now, have not been there in ages.
But it was quite far from the TV tower.
https://en.wikipedia.org/wiki/Media_Park_(Hilversum)
http://panteltje.com/pub/mediapark.gif

 

[Joerg]

On 2019-07-16 08:37, John Larkin wrote:

On Tue, 16 Jul 2019 07:25:23 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-16 06:56, John Larkin wrote:
On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.


And each would probably cost $2M+ on the market, leaky plumbing or not.
No 10 horses would drag me to live in S.F.

I love this place. Most visitors see the parts of the city that we
never go to.

S.F. has deteriorated a lot. Sometimes you have to step over people
sleeping on the sidewalk, occasionally over some barf, et cetera.
Sacramento is heading in that direction a well, fast, and for obvious
reasons. Well, not obvious to certain politicians which are
unfortunately in the absolute majority right now.

I like a more rural setting such as our area in the Sierra foothills.
And it's not hick town, there is high-tech going on. I just came back
from a dog walk and right in front of our driveway had a chat with a
neighbor's dad. He said his company needs EMC consulting pretty soon for
some big switch mode converters. I guess stuff like that only happens in
the US.

I have a mostly inaccessable/hidden loft outside of my office. I bet I
could put up a big, 100 sq feet at least, resonated loop antenna and
get enough RF to light up an LED. Some LEDs are visible in room light
at 1 uA, and in the dark at a few nA.

Can a loop antenna be multiple wavelengths long and do any good?

Yes.

http://www.ece.mcmaster.ca/faculty/nikolova/antenna_dload/current_lectures/L12_Loop.pdf

In your area you may have the sparks flying if the ends of your loop
antenna get too close.

... The
"resonance" would actually be multiple cycles of transmission line
delay. That should work. What polarization to AM/FM/TV transmitters
use? Antennas are complicated.

AM in the US is usually vertically polarized because they use a very
tall tower fed at the bottom. In other countries that sort of expense
isn't always palatable so they sometimes use dipoles strung between a
couple of high points and then it's horizontal. Horizontal has the
downside of nulls in two directions, making the range non-circular and
that's bad for listener numbers and thus advertizing revenue.

FM is also vertical but that gets bent along the path, especially when
looking at car antennas.

TV is generally horizontal with very few exceptions, for example in
mountainous regions.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Tue, 16 Jul 2019 17:19:45 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 08:26:17 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
deqried1d0ifvnvldqr8arkkialcv1iakd@4ax.com>:

On Tue, 16 Jul 2019 14:18:41 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?

Megawatts.

That scares me.


What frequency is that?

Everything. On a spactrum analyzer, the AM, FM, and TV bands are about
full. And the tower is used for police and fire comms too. It
overlooks the entire city, and then some.




I bet they could have wireless LED night lights.

Long ago I lived not so far away from a TV tower:
https://en.wikipedia.org/wiki/Gerbrandy_Tower
about 100kW, I read they had at one point 400 kW running,
there are some FM radio antennas on it too.
I could get the video with a crystal detector on Ch 4 (about 65 MHz).
Designed and build my own transistor TV in school days.
Now it is all lower power digital terrestrial.

Tested my ham transmitter with a neon bulb in the garden

Here's my Pockels Cell driver:

https://www.dropbox.com/s/mt2ym6ukuizoy9q/Neon_4.jpg?raw=1


Yes, we discussed that before, just do not put the neon _in_ the coil,
it may scatter pieces of glass, I killed one that way, was lucky,
was a dual envelope neon tuning indicator... Maybe from some radar..

Stick an NE-2 in a microwave oven. Fun.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Joerg]

On 2019-07-16 11:22, John Larkin wrote:

On Tue, 16 Jul 2019 10:28:05 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-16 08:37, John Larkin wrote:
On Tue, 16 Jul 2019 07:25:23 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-16 06:56, John Larkin wrote:
On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.


And each would probably cost $2M+ on the market, leaky plumbing or not.
No 10 horses would drag me to live in S.F.

I love this place. Most visitors see the parts of the city that we
never go to.


S.F. has deteriorated a lot. Sometimes you have to step over people
sleeping on the sidewalk, occasionally over some barf, et cetera.

That's downtown. We don't go downtown.

It'll spread fast. When I visited you guys on Otis Street and we walked
to Zeitgeist there were several folks sleeping on the sidewalks.

Sacramento is heading in that direction a well, fast, and for obvious
reasons. Well, not obvious to certain politicians which are
unfortunately in the absolute majority right now.

SF has decided that "homeless" people who live in cars and trucks and
RVs need support too. So we'll have free full-service RV parks all
over town. That's going to get interesting.

Ever since some <expression censored> judge declared it ok that they can
camp just about anywhere they ... just do that. Parts of Sacramento have
become so bad that people start avoiding those areas. Which will
ultimately result in business failures. Even where we live it's becoming
worse. There is one shopping area we don't use anymore, where people now
occasionally use trash cans as open air outhouses.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Tue, 16 Jul 2019 10:28:05 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-07-16 08:37, John Larkin wrote:
On Tue, 16 Jul 2019 07:25:23 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-07-16 06:56, John Larkin wrote:
On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

I bet they could have wireless LED night lights.


And each would probably cost $2M+ on the market, leaky plumbing or not.
No 10 horses would drag me to live in S.F.

I love this place. Most visitors see the parts of the city that we
never go to.


S.F. has deteriorated a lot. Sometimes you have to step over people
sleeping on the sidewalk, occasionally over some barf, et cetera.

That's downtown. We don't go downtown.

Sacramento is heading in that direction a well, fast, and for obvious
reasons. Well, not obvious to certain politicians which are
unfortunately in the absolute majority right now.

SF has decided that "homeless" people who live in cars and trucks and
RVs need support too. So we'll have free full-service RV parks all
over town. That's going to get interesting.



--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Lasse Langwadt Christense]

tirsdag den 16. juli 2019 kl. 22.01.45 UTC+2 skrev Phil Hobbs:

On 7/16/19 11:26 AM, John Larkin wrote:
On Tue, 16 Jul 2019 14:18:41 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?

Megawatts.

What frequency is that?

Everything. On a spectrum analyzer, the AM, FM, and TV bands are about
full. And the tower is used for police and fire comms too. It
overlooks the entire city, and then some.


Just one nickel-plated connector could cause some havoc.

https://youtu.be/lMuJKsUjD_o

 

[Phil Hobbs]

On 7/16/19 11:26 AM, John Larkin wrote:

On Tue, 16 Jul 2019 14:18:41 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Tue, 16 Jul 2019 06:56:47 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
eqlrielfeeeovifsku3olimru2635svnld@4ax.com>:

On Tue, 16 Jul 2019 06:53:17 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 15 Jul 2019 16:41:44 -0700) it happened John Larkin
jjlarkin@highland_snip_technology.com> wrote in
0e3qie9ivv3io0dcsf0uhihf61m4lbo028@4ax.com>:

When I used to work on Judah Street, I drove to work over a road on
Twin Peaks, just under the Sutro tower. My old ratty Fiesta had a
cheap add-on radio. I could hear buzzing from the speakers with the
radio turned off.

People live up there.

It is common, my Sony alarm clock FM radio also makes noise when my cellphone interacts with the tower,
even with that radio off, so do my PC speakers.



Here's the street. That's 22 megawatts right above those houses.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Mega Watt? not kW?

Megawatts.

What frequency is that?

Everything. On a spectrum analyzer, the AM, FM, and TV bands are about
full. And the tower is used for police and fire comms too. It
overlooks the entire city, and then some.

Just one nickel-plated connector could cause some havoc.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Jeff Liebermann]

On Tue, 16 Jul 2019 06:56:47 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

Here's the street. That's 22 megawatts right above those houses.
https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Nope. The 22 MegaWatts might be the EIRP (Equivalent Isotropically
Radiated Power), which is the transmitter RF output power, minus any
coax cable or waveguide loss, times the antenna gain. The antenna
gain is achieved by reducing the vertical beamwidth. Such high power
levels may have some exposure relevance at the altitude of the
antenna, but not on the ground, which is well outside the main lobe.

Also, the 22 MegWatt number seems much too high.

2018 RF Exposure Report
<https://sutrotower.com/wp-content/uploads/2018/08/Sutro-200-Point-R-F-Measurements-2018.pdf>

Major
Xmitters CH kW EIRP
KGO-TV D07 24
KPIX-TV D29 1,000
KQED D30 1,000
KFSF-DT D34 370
KRON-TV D38 1,000
KCNS D39 1,000
KCSM-TV D43 500
KTVU D44 1,000
KBCW D45 1,000
KOIT(FM) 243 24
KSOL(FM) 255 6.1
KFOG(FM) 283 7.1

Total: 6,931.2 kW EIRP
or about 7 MegaWatts

"The maximum RF exposure level measured at any of the 212 locations
surrounding Sutro Tower was 6.0% of the most restrictive FCC public
exposure limit."


<https://sutrotower.com/for-our-neighbors/>
"The radiation from Sutro Tower is 8.4% of the FCC limit
at the point of maximum exposure under normal conditions."

"When broadcasters use their auxiliary antennas, which
are located lower on the tower than their primary antennas,
the maximum radiation level can rise, but is never more
than 15% of the FCC limit."

>I bet they could have wireless LED night lights.

If the light was in the main lob of the antennas, I could probably
cook my dinner. However, on the ground, at 8.4% of the FCC limit,
methinks not.

The highest public exposure allowed by the FCC in the VHF/UHF FM and
TV bands is a power density of 0.2 mW/cm^2 or 2 watts/sq-meter. 8.4%
(maximum measures) is 0.016 mW/cm^2 or 0.16 watts/sq-meter.

[Gotta run. I'll finish this later...]

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Tue, 16 Jul 2019 13:27:09 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>https://youtu.be/lMuJKsUjD_o

That's the base insulator from what appears to be an AM broadcast
station. The tower is the transmit antenna and is NOT grounded.
Judging by the size of the sparks, my guess(tm) is about 20,000 volts
across the base insulator (based on 30kV/cm). The weeds are full of
water and make a fairly good conductor. Usually, cleaning the weeds
and debris from around the tower is done with the transmitter turned
off, or at a greatly reduced power level. The "burns" on his hands
were caused either by the heating of the water in the weeds burning
his hands or by the RF arcing through the gloves, causing local spot
heating in the gloves.




--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558